Patent GB-1467176-A (GB)
Title: Pneumatic apparatus for use with an automatic firing weapon
IPC: F41A19/55
Filed: 1974-02-28
Abstract: 1467176 Pneumatic systems for automatic weapons WERKZEUGMASCHINENFABRIK OERLIKON-BUHRLE AG 28 Feb 1974 [2 March 1973] 9071/74 Heading F1P [Also in Division F3] A piston and cylinder device 1, 3 for operating an automatic firearm trigger is controlled by a valve 21, biased to a piston non-actuating position and operable to a position for piston, and thus trigger, actuation by compressed air via a selector valve 34 from either of two valve arrangements, one of which causing momentary movement of the piston 1 for single shot firing and the other causing maintenance of the piston in its actuated position for continuous firing; control valves 40, 50, 60, 70 connect the valve arrangements to an actuation valve 80 and operate the selector valve 34 for selected operation of the arrangements. The control valves 40, 50, 60, 70, e.g. slide valves, are actuated in various combinations by a multi-position switch to produce the various firing modes. In the safety position, the valves 40, 60 vent conduits 41, 61 to atmosphere and valves 50, 70 interrupt flow in conduits 51, 71 thus causing no flow through the selector valve 34 to piston-cylinder control valves 21, 22 so that trigger actuating piston-cylinder actuators 1, 2, have their working chambers 5, 6 vented to atmosphere. For the single shot mode, valve 60 is actuated to allow flow in conduit 61 upon actuation of valve 80, foot operated, to displace the valve 34 so that air from a source 67 passes to the valve 21, 22 thus communicating the chambers 5, 6 with sources 23, 24 for trigger actuation. As a result, air passes through a checkvalve 19 to a valve 36 of the first arrangement for displacement thus causing the control lines of valves 21, 22 to be vented and cutting off the air to the chambers 5, 6 after the single actuation. For a low cadence series firing mode, as well as the valve 60 allowing flow, the valve 70 allows flow from the source 67, via the valve 36 after the first actuation of the actuators 1, 2, via a throttle 68 to an accumulator tank 72 which after a time period actuates a valve 75 of the first arrangement to connnect a control line 78 for a valve 63 of the first arrangement with a source 76. Thus the valve 63 connects the valve 36 with a source 64 for the valves 21, 22 to be connected to source 67 for further actuation. After each actuation, the tank 72 is vented via a check-valve 74 to atmosphere via the valve 36. For a limited series firing mode, the valves 60, 70 revert to their "safety" position but the valves 40, 50 allow flow in the conduits 41, 51, to that the valves 21, 22 are connected with a source 79 via the valve 80 and conduits 55, 41, 31. Furthermore a tank 52 builds up pressure to eventually displace a valve 43 of the second arrangement to displace a valve 39 of this arrangement to interrupt air to the valves 21, 22 after a limited number of shots. For the normal series firing mode, the valve 50 reverts to its interrupting position to prevent the delayed actuation of the valve 39 so that firing occurs until the foot actuation valve 80 is de-actuated. Firing also stops if valves 29, 30 are displaced by feelers associated therewith indicate that the ammunition belt is depleted.